Microbicidal agents are generally used to stop microorganisms from proliferting or to destroy them altogether. Hitherto, quaternary ammonium compounds, such as benzalkonium chloride or cetyl trimethyl ammonium chloride, have been successfully used as microbicidal agents. Unfortunately, it has been found that such compounds are not readily biodegradable in sewage treatment plants. Accordingly, there is a need for microbicidal compounds which are comparable in their performance with the quaternary ammonium compounds, but which have distinctly improved biological degradability.
U.S. Pat. No. 3,910,971 describes quatemary carboxylic acid alkanolamine ester salts obtainable by reaction of 2-dimethylamino-2-methyl-1-propanol with fatty acids and subsequent quatemization as microbicidal agents. However, these compounds are largely ineffectual against the gram-negative bacterium Pseudomonas aeruginosa which is a disadvantage in view of the commonly occurring waterborne germ which leads above all to product contamination.
European patent application EP 0 461 419 describes poly(oxy-lalkylene)aminoalkanol esters and ammonium compounds thereof which are also said to show microbicidal activity. However, these compounds have to contain at least one hydroxyisopropyl group and bear a methyl group at the nitrogen atom. No mention is made of the effectiveness of these compounds against bacteria, particularly against the commonly occurring bacterium Pseudomonas aeruginosa. 
The problem addressed by the present invention was to provide microbicidal compounds which would be comparable in their microbicidal activity with conventional quaternary ammonium compounds. Above all, the compounds would also be microbicidally active against the commonly occurring bacterium Pseudomonas aeruginosa. In addition, the compounds would show better biodegradability than the conventional quatemary ammonium compounds.
The present invention includes the use of quaternary carboxylic acid alkanolamine ester salts as microbicidal agents, more particularly in detergents, disinfectants, preservatives, fabric softeners, cosmetics, cooling lubricant emulsions and in coating compositions. The present invention also relates to detergents, fabric softeners, disinfectants, preservatives, cosmetics, cooling lubricant emulsions and coating compositions containing these quaternary carboxylic acid alkanolamine ester salts.
It has been found that special quaternary carboxylic acid alkanolamine ester salts satisfy this requirement.
Accordingly, the present invention relates to the use of quaternary carboxylic acid alkanolamine ester salts corresponding to general formula (I): 
in which
R1CO is an acyl group containing 2 to 18 carbon atoms,
R2 and R3 independently of one another represent an alkyl group containing 1 to 16 carbon atoms or a group with the formula CH2xe2x80x94CH2xe2x80x94Oxe2x80x94R5,
R4 is an alkyl group containing 1 to 4 carbon atoms,
R5 is hydrogen and/or R1CO and
Xxe2x88x92 is an anion,
as microbicidal agents.
The quaternary carboxylic acid alkanolamine ester salts are compounds known from the literature which are often also referred to as xe2x80x9cesterquatsxe2x80x9d. They are generally prepared by esterification of the alkanolamines with carboxylic acids in the presence of hypophosphorous acid, passing air through the reaction mixture and then quatemizing the esterification product. U.S. Pat. Nos. 3,915,867, 4,370,272, EP-A0 239 910, EP-A-0 293 955, EP-A0 295 739 and EP-A-0 309 052 are cited here are representative of the abundant prior art available on the subject.
According to the invention, the quaternary carboxylic acid alkanolamine ester salts are prepared by methods known per se, alkanolamines corresponding to formula (II): 
in which R2 and R3 are as defined for formula (I), with the proviso that, where R2 and/or R3 represent(s) the group CH2CH2OR5, R5 is hydrogen, being esterified with carboxylic acids corresponding to the formula R1COOH. The alkanolamines corresponding to formula (II) may also be transesterified with esters of the described carboxylic acids to give the compounds of formula (I) used in accordance with the invention. Suitable alkanolamines are dialkyl ethanolamines (R2, R3=alkyl group containing 1 to 16 carbon atoms), such as dimethyl ethanolamine, methylethyl ethanolamine, diethyl ethanolamine, methylbutyl ethanolamine and/or methylhexyl ethanolamine, monoalkyl diethanolamines (R2=CH2CH2OH; R3=C1-16 alkyl group), such as methyl diethanolamine, ethyl diethanolamine and/or butyl diethanolamine, and/or triethanolamines (R2, R3=CH2CH2OH). Monoalkyl diethanolamines and/or triethanolamines are preferably used.
Suitable carboxylic acids R1COOH are aliphatic saturated and/or unsaturated carboxylic acids, more particularly aliphatic saturated carboxylic acids, such as acetic acid, propionic acid, butyric acid, caproic acid, caprylic acid, capric acid, pelargonic acid, lauric acid, myristic acid, palmitic acid and the technical mixtures thereof obtained, for example, in the pressure hydolysis of natural fats and oils. Aliphatic saturated carboxylic acids containing 8 to 12 carbon atoms are preferred so that R1CO in formula (I) is preferably an aliphatic saturated acyl group containing 8 to 12 carbon atoms.
The quantity ratio of carboxylic acids or carboxylic acid esters to the alkanolamines is determined by the required degree of esterification of the free hydroxyl groups of the alkanolamines. In the case of the preferred monoalkyl diethanolamines and triethanolamine, all or only some of the free hydroxyl groups can be esterified with the carboxylic acids. If the hydroxyl group is not esterified, R5 in general formula (I) stands for R1CO. The esterification may be complete or partial. Where esterification is partial, the average degree of esterification of thexe2x80x94overallxe2x80x94free hydroxyl groups in the case of the monoalkyl diethanolamines is preferably in the range from 1.2 to 1.7 and, in the case of the triethanolamines, is preferably in the range from 1.2 to 2.5, i.e. mixtures of mono-, di- and optionally triesters of the di- or triethanolamines with carboxylic acids are present. According to the invention, at least two of the free hydroxyl groups in the triethanolamine are esterified with carboxylic acids. Instead of the carboxylic acids, ester derivatives thereof with the alkanolamines may also be reacted.
The subsequent quaternization is carried out by the methods known in this field and leads to the quaternary carboxylic acid alkanolamine ester salts corresponding to general formula (I). Compounds with the formula R4X, where R4 is as defined for formula (I) and preferably stands for a methyl group, are used for the quaternization. Where X in general formula (I) stands for formate, acetate, tartrate, dicarboxylate, citrate, halide, sulfate or nitrate, the usual quaternization was followed by an anion exchange.
According to the invention, it is particularly preferred to use compounds of formula (I) in which R2 is a group CH2CH2OR5 and R3 is a methyl group and/or in which R2 and R3 stand for a group CH2CH2OR5 where R5 is as previously defined. Examples of particularly suitable compounds are dimethyl diethanolammonium dicaprylic acid ester methosulfate, methyl triethanolammonium tricaprylic acid ester methosulfate, methyl triethanolammonium dicaprylic acid ester methosulfate and dimethyl diethanolammonium dipelargonic acid ester methosulfate.
According to the invention, the described compounds are used as microbicidal agents. In the context of the invention, microbicidal agents are understood to be chemicals which are capable of destroying, or preventing the proliferation of, bacteria, yeasts, fungi, viruses and protists.
Microbicidal agents corresponding to this definition may be used in any products where a corresponding effect is required. They are preferably used in detergents/cleaners, for example in manual dishwashing detergents, multipurpose cleaners, sanitary cleaners, fabric softeners for the antimicrobial finishing of textiles, in disinfectants, for example in the home and in hospitals, in preservatives, for example for preserving industrial raw materials and products, in cooling lubricant emulsions, in cosmetics and in coating compositions, such as glues, paints and wood preservatives.
The compounds used in accordance with the invention are effective against bacteria in quantities of only  greater than 5 mg/l, expressed as active substance and based on the particular preparation. They are generally used in quantities of 5 to 5,000 mg/l and preferably in quantities of 50 to 1,000 mg/l, expressed as active substance and based on the particular preparation. In the case of concentrates, the quaternary carboxylic acid alkanolamine ester salts may also be used in larger quantities. However, if the concentrates are diluted with water by the end user, the quantities used are again in the range mentioned above.
The compounds used in accordance with the invention may be used in pure form or in the form of solutions. Suitable solvents are water and/or lower alcohols, more particularly ethanol, propanediol and/or isopropanol. Lower alcohols or aqueous mixtures thereof are recommended above all for quatemary carboxylic acid alkanolamine ester salts of the described type which contain more than two acyl groups bearing more than 6 carbon atoms.
The present invention also relates to detergents/cleaners containing quaternary carboxylic acid alkanolamine ester salts as microbicidal agents, to preservatives containing quaternary carboxylic acid alkanolamine ester salts as microbicidal agents, to cosmetics containing quatemary carboxylic acid alkanolamine ester salts as microbicidal agents, to disinfectants containing quatemary carboxylic acid alkanolamine ester salts, to cooling lubricant emulsions containing quaternary carboxylic acid alkanolamine ester salts and to fabric softeners containing quaternary carboxylic acid alkanolamine ester salts as microbicidal agents. The quaternary carboxylic acid alkanolamine ester salts may be present in such preparations in the quantities mentioned above. In addition, the preparations may of course also contain other microbicidal agents and other typical ingredients in typical quantities.
Thus, the following anionic, nonionic and/or amphoteric or zwitterionic surfactants, for example, may be present in the detergents/cleaners:
Anionic surfactants: alkyl benzenesulfonates, alkanesulfonates, olefin sulfonates, alkyl ether sulfonates, glycerol ether sulfonates, methyl ester sulfonates, sulfofatty acids, alkyl sulfates, fatty alcohol ether sulfates, glycerol ether sulfates, hydroxy mixed ether sulfates, monoglyceride (ether) sulfates, fatty acid amide (ether) sulfates, sulfosuccinates, sulfosuccinamates, sulfotriglycerides, ether carboxylic acids, alkyl oligoglucoside sulfates, alkyl (ether) phosphates and protein fatty acid condensates. Nonionic surfactants: fatty alcohol polyglycol ethers, alkyl phenol polyglycol ethers, fatty amine polyglycol ethers, fatty acid amide polyglycol ethers, fatty acid polyglycol esters, alkoxylated triglycerides, alkyl oligoglycosides, sugar esters, sorbitan esters, polysorbates, polyol fatty acid esters, amine oxides, fatty acid alkanolamides, alkyl lactams and fatty acid-N-alkyl glucamides. Amphoteric or zwitterionic surfactants: alkylamidobetaines, aminopropionates, aminoglycinates, imidazolinium betaines and sulfobetaines.
The detergents/cleaners may also contain typical ingredients, such as builders, salts, bleaching agents, optical brighteners, redeposition inhibitors, solubilizers and enzymes.
The preservatives may contain alcohols, aldehydes, acids, esters, phenols, terpenes and/or complexing agents.
The disinfectants may also contain one or more of the above-mentioned anionic, nonionic and/or amphoteric or zwitterionic surfactants and also water, alcohols, complexing agents and other microbicidal compounds.
The cooling lubricant emulsions generally contain an aqueous phase and an organic phase, the organic phase generally being formed by mineral oils or vegetable oils. In addition, emulsifiers, optionally extreme pressure additives, corrosion inhibitors and/or complexing agents are mostly present.
The cosmetics may also contain one or more of the above-mentioned anionic, nonionic and/or amphoteric or zwitterionic surfactants and optionally water or a water phase, alcohols, optionally an oil phase, emulsifiers and optionally other microbicidal compounds. Typical additives, such as abrasives, pearlizing pigments, dyes, perfumes, optionally other preservatives, gel formers and/or conditioning and care principles, may be present